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V5F/V8 UL Certification / Safety Question


Joe Holliday

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Are the Inmotion devices such as the V5F and V8 UL certified? Have there ever been any reports of fires or battery explosions with their products? I've been trying to decide between a V5F+ and a Segway S1 which is UL 2272 certified, but the Inmotion website doesn't mention any sort of safety certifications. The V5F definitely has preferable specs to me, but I'm concerned about safety after seeing so many reports of hoverboard fires.

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26 minutes ago, Joe Holliday said:

Have there ever been any reports of fires or battery explosions with their products?

No. I don't think there has been any report of a branded EUC catching fire so far. Plus, InMotion is at the top end when it comes to production quality reputation, but I can't speak to their certifications as I don't know.

There has been one vid on youtube of an EUC catching fire during driving though. I am not sure if it was real, it looked a little suspicious.

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From @Jason McNeil's comparison chart (https://www.ewheels.com/comparing-segway-ninebot-s1-inmotion-v5f-feature-review/) it appears that the V5F is not UL certified, which had me concerned to, but I asked Jason about this and he assured me that they are safe.  I don't know what goes into this certification, so I don't want to downplay it's significance, but I have been extremely happy with my inmotion purchase and the service that @Jason McNeil has provided!

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2 hours ago, Joe Holliday said:

Are the Inmotion devices such as the V5F and V8 UL certified?

The costs for obtaining a UL2272 certification on an Electric Unicycle are considerable, approximately $38,000 directly to UL, in addition to providing 16-20 Wheels in order to be destroyed in various ways. For Inmotion they made the call, that for the time being, these costs exceeded the additional sales likely of being able to sell to marketplaces like Amazon.com. 

Keep in mind that the battery cells & standard chargers are certified, which were the causes of most incendiary hoverboard incidents.

Technically speaking, when the wheel diameter is only 6.5-10" & so low to the ground with a load of say 300lbs, the dynamic forces in order to keep this person balanced on a relatively low-powered machine overtax the design capabilities of those poor 20 battery cells. Is it any wonder they fail catastrophically? Compare this to an Electric Unicycle where the motion, & therefore the power output, is continuous, & the cell count on a decent Wheel is at least double this.  

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41 minutes ago, Jason McNeil said:

Technically speaking, when the wheel diameter is only 6.5-10" & so low to the ground with a load of say 300lbs, the dynamic forces in order to keep this person balanced on a relatively low-powered machine overtax the design capabilities of those poor 20 battery cells.

I don't see how small wheels or underpowered motors should be a reason for battery problems. An underpowered motor should rather prevent battery problems, as it can drain less power.

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4 hours ago, Mono said:

I don't see how small wheels or underpowered motors should be a reason for battery problems. An underpowered motor should rather prevent battery problems, as it can drain less power.

Think about it, the control-system on any self-balancing device has one primary mission, to remain upright. With smaller motor/wheel & large burden to support—especially when starting out, a Rider's movements are going to be jerky & uncontrolled—the system is going throw whatever power it can to keep this person upright, maxing out the battery's range ability to provide sufficient power for what's demanded of them. This scenario is not uncommon with the Boards. 

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13 minutes ago, Jason McNeil said:

the system is going throw whatever power it can to keep this person upright

which would be the more power the stronger the motor is, which would make a battery failure with a stronger motor more likely

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Let's take the case of a powerful Wheel, which might have 2KW of battery power available but only needs only 500W of power to cruise at 35kph (not exactly numbers but for illustration). Which means the battery is only giving 25% of what it's capable of.

Now the the case of the Board, momentary requires peak of 750-1000W to keep an overweight person from toppling over but can only provide 700W, the cells are taxed beyond what they're able to give. Result: cells get very hot, increasing the statistical odds of cell failure. This is not theoretical, the empirical evidence of the service life of boards is just atrocious, according to one supplier I know they can expect 25-30% of battery failures in a year of moderate use. 

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2 hours ago, Jason McNeil said:

Let's take the case of a powerful Wheel, which might have 2KW of battery power available but only needs only 500W of power to cruise at 35kph (not exactly numbers but for illustration). Which means the battery is only giving 25% of what it's capable of.

Now the the case of the Board, momentary requires peak of 750-1000W to keep an overweight person from toppling over but can only provide 700W, the cells are taxed beyond what they're able to give. Result: cells get very hot, increasing the statistical odds of cell failure. This is not theoretical, the empirical evidence of the service life of boards is just atrocious, according to one supplier I know they can expect 25-30% of battery failures in a year of moderate use. 

@Jason McNeil, sure, but the reason of failure is a small (and possibly cheap) battery, it is not a small motor. All else being equal, making the motor smaller will not lead to more battery failures, while making the battery smaller will.

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3 hours ago, Jason McNeil said:

Let's take the case of a powerful Wheel, which might have 2KW of battery power available but only needs only 500W of power to cruise at 35kph (not exactly numbers but for illustration). Which means the battery is only giving 25% of what it's capable of.

Now the the case of the Board, momentary requires peak of 750-1000W to keep an overweight person from toppling over but can only provide 700W, the cells are taxed beyond what they're able to give. Result: cells get very hot, increasing the statistical odds of cell failure. This is not theoretical, the empirical evidence of the service life of boards is just atrocious, according to one supplier I know they can expect 25-30% of battery failures in a year of moderate use. 

But that is exactly the problem. The stupid circuit cuts off to open circuit to protect the battery and the rider goes flying.  The electronics need more engineering to just modulate the current to not exceed the maximum of the battery capability.  Then the rider would feel that the board is not maintaining the angle and becoming soft and the rider then has a chance to back off preventing a flying rider.

 thats is all we are saying shutting the wheel when capability is exceeded is a bad lazy design. 

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